In order to add a new article to yoru Drupal you should first login to your Dashboard. Then proceed to Content-> Add Content .
There you will see the option for adding an Article .
There you will see a screen with plenty of details that you may add to your article. You should first fill in the Title of your article, then you may add Tags to it ( Tags are key words of your content that will serve to the search engines) . You should fill in the Body and you also have the option of adding an Image to it.
At the bottom of the screen you will see several more options. There you will be able to add a Menu link for the Article , write a Revision message to the other admins of the website, set URL aliases ( simple words giving better understanding for your content to your visitors) . From this bottom menu you can also open/close the option for your visitors to leave comments below your article, you can change the Authorship and choose if it should be Published, Promoted on the front page or Sticky at the top of a list
Then just clcik on Save and off you go! You have your first Drupal article!